Small engine problem (obviously OT) (SOLVED)

[vanagon40]

I remember not too long ago, someone had a small engine questions, and it seemed there were several folks with lots of experience ready to help.  So here is my problem.  My Briggs & Stratton engine smokes like a chimney.

It’s a 500cc, 16.5hp Intek on a 2008 or 2009 Dixon ZTR.  I bought the mower used in 2012.  It always ran great until the end of last season when it suddenly started smoking and burning oil.  It was not gradual, it started suddenly.  (Sitting in the barn over the winter did not cure the problem.)

I have changed the oil and filter every season.  I clean or change the air filter every season (and the air filter does not get that dirty).  I mow a flat yard less than one acre in central Indiana.  I doubt I used it much over 50 hours per year (and maybe not that much).  The only neglected maintenance was by the original owner who “bragged” that even though he had owned the mower for three years, he used it so little that it still had the original oil and he had never greased a fitting.  As he owned a car wash, I think he washed it every time he used it and it did look like new.  He claimed under 40 hours of use.

I checked the compression and read 80 to 85 PSI, but I think there may be a compression release.

My thought was to purchase a new head gasket set (only $17), pull the head, and check the crankcase breather while I’m pulling the head.

It still runs fine, just leaves a trail of smoke, and I have to add oil before I start and between the front yard and back yard.  I don’t add much, just enough to raise the level from the bottom of the operating range to the top.  Before last fall, I almost never had to add oil (maybe once per season at most, and I check it every time I mow).

Model 31E777 Type 0115 G1.

Any other suggestions?

[Davemn]

Stuck rings?

[slider]

Mine done same thing..tore it down and the oil ring was broken,and had scratched up the cyl  wall and piston pretty bad,not hard to fix  just time wise it is..good  luck on yours.

[DK]

Remove the spark plug, pour I tbsp. engine oil into cylinder, turn it over 4-5 times & check compression.

If it significantly increases, you have a ring problem.

Given 85 psi. on a B&S, I think it's most likely being sucked in through a bad intake valve seal.

There is usually a crankcase breather behind the valve case. Clean it out as this could likely be the problem.

Dan

[Jess Tolbirt]

i am with dk on this one,, if the air cleaner is clogged it has to get air from somewhere and its usually through the breather,, you say new filter? then run some block flush through it and see if it will un stick something,,only three places it can get oil from to make it smoke,, intake, valve seals, or cylinder..

[3W-lonerider]

I'd say you have a blown head gasket. the way those head gaskets are set up. it blows between the cyl, and the oil galley for the rods.
after removing all the covers to get the head off shouldn't take ya but about an hour to fix from start to finish.
and yes it will smoke so bad that there wouldn't be a mosquito within 10 miles of that mower. and it happens all at once.
the reason it happens is the high engine solenoid that is mounted on the bottom of the carb float bowl. the rubber tip wears out and it starts backfiring everytime you shut it off.

[vanagon40]

. . . .  it starts backfiring everytime you shut it off.

BINGO.  It absolutely does.  It will be the middle of June before I get a change to change it, so my lack of a solution is certainly not indifference to the great responses.

[On second though I'm going to order the gasket kit right now and maybe be able to fix it some night before I go on vacation.]

 

[3W-lonerider]

make sure you order a new solenoid for on the bottom of the carb. I know they are expensive but if you don't replace it you'll just keep blowing head gaskets.

[Jess Tolbirt]

mine backfires when i shut it off too, other than that it runs fine,,so the solenoid is the problem causing that? mine is the 25 horse v-twin briggs..do you think the head gaskets are blown? it doesnt smoke yet..

[3W-lonerider]

if it's not smoking then no your head gasket is not blown.. it may last awhile without blowing no telling how long but eventually it will happen.
you will know when it happens though.
 engine will still run fine but will smoke like an old steam engine. and loss of power.

[vanagon40]

Got the head gasket changed tonight.  Took more like 4 hours than 1.

I'm 99% sure that was the problem.  You can see the gap in the gasket and I could also see the blow-by trial on the engine block.

Just one stupid question.  The gasket set came with two (2) head gaskets.  I assume I was only supposed to one--the one one that matched the one I took off?

Thanks for all the advice.

[Jess Tolbirt]

Got the head gasket changed tonight.  Took more like 4 hours than 1.

I'm 99% sure that was the problem.  You can see the gap in the gasket and I could also see the blow-by trial on the engine block.

Just one stupid question.  The gasket set came with two (2) head gaskets.  I assume I was only supposed to one--the one one that matched the one I took off?

Thanks for all the advice.

i believe you assume right because if one is different then you couldnt use it anyway..

[vanagon40]

FINAL UPDATE

I have now used the mower several times and all problems are cured.  No more smoking; no more oil consumption.

No doubt it was a blown head gasket.